The crystalline polyamides represented by Nylon 6, Nylon 66, etc., have widely been used as a fiber for cloths and industrial materials or general use engineering plastics due to their excellent characteristics and easiness in melt molding, but on the other hand, it has been pointed out the problems that change in physical properties due to water absorption, deterioration in an acid, high temperature alcohol or hot water, etc. Thus, demands for obtaining a polyamide having more excellent dimensional stability and chemical resistance have been heightened.
A polyamide resin using oxalic acid as a dicarboxylic acid component is called as a polyoxamide resin, has been known to have a high melting point and low water absorption rate as compared with the other polyamide resins having the same amino group content (Patent Literature 1), and expected to be utilized in the field where the conventional polyamide can be difficultly used, which involves the problem of changing physical properties due to absorption of water.
Polyoxamide resins using various aliphatic linear diamines as a diamine component have heretofore been proposed. For example,
in Non-Patent Literature 1, a polyoxamide resin using 1,6-hexanediamine as a diamine component has been disclosed,
in Non-Patent Literature 2, a polyoxamide resin in which a diamine component is 1,9-nonanediamine (hereinafter also referred to PA92) has been disclosed,
in Patent Literature 2, a polyoxamide resin using various diamine components and dibutyl oxalate as a dicarboxylic acid ester has been disclosed,
in Patent Literature 3, a polyoxamide resin in which two kinds of diamines of 1,9-nonanediamine and 2-methyl-1,8-octanediamine were used as diamine components has been disclosed.